Shell designed for securing in a mortar and mortar designed for such a shell

ABSTRACT

The invention relates to a shell ( 1 ) intended for firing from a weapon ( 6 ), preferably a mortar weapon ( 6 ), the shell ( 1 ) being designed for securing the shell ( 1 ) in a mortar weapon ( 6 ) in order thereby to prevent movement of the shell ( 1 ) when adjusting the angle of elevation of the weapon ( 6 ). According to the invention this is achieved in that the shell ( 1 ) comprises a locking part ( 19, 28, 37 ), the locking part ( 19, 28, 37 ) forming an integral part of the shell ( 1 ) and being designed so that the shell ( 1 ) after ramming home is locked to a corresponding securing part ( 19 ) in the mortar ( 6 ). The invention also relates to a mortar ( 6 ) intended for firing said shell ( 1 ), the mortar ( 6 ) being characterized in that the mortar ( 6 ) comprises a corresponding securing part ( 19 ) for locking the shell ( 1 ).

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Phase filing under 35 U.S.C. §371 ofPCT/SE2008/000612 filed on Oct. 29, 2008; and this application claimspriority to Application No. 0702645-3 filed in Sweden on Nov. 30, 2007under 35 U.S.C. §119; the entire contents of all are hereby incorporatedby reference.

The present invention relates to a shell intended for firing from aweapon, preferably a mortar weapon, the shell being designed for lockingin a mortar to prevent movement of the shell when adjusting the angle ofelevation of the mortar prior to firing. The invention also relates to amortar weapon designed for firing said type of shell and a systemcomprising said shell and mortar.

BACKGROUND OF THE INVENTION

Conventional mortar weapons (also referred to as mortars) and mortarammunition has looked pretty much the same since the days of the FirstWorld War. Conventional mortars are not especially suited to mounting onvehicles. Where installed on vehicles extensive manual handling isrequired, both of the mortar by redeploying vehicles and of the shell bychanging the number of charges. It is necessary either to sacrificearmour protection and to load the mortar manually from open hatches, orto design complicated loading apparatus which moves shells from theinside of the vehicle to the muzzle of the mortar barrel. A furtherproblem is that the shell lies loosely in the barrel, which means thatthe mortar can only be fired with a high angle of elevation. If attemptsare made to tip the mortar, that is to say to lower the barrel below acertain angle of elevation, there is a great risk that the shell willshift or slide out of the barrel.

Devices to prevent the shell shifting prior to firing, for example whenadjusting the angle of elevation of the barrel, have long been known. GB2 260 390 A discloses and describes a device for locking a shell. Thelocking device consists of a locking plate and snap fastening. Thelocking device is fixed to the rear part of the shell, behind the finsof the shell, following which the shell is rammed home into the weapon.The locking plate is disc-shaped and has an outside diameter greaterthan the inside diameter of the barrel. When ramming the shell home inthe barrel the locking plate will be rammed home against a shoulder,which is formed due to the fact that the breech opening diameter of thebarrel has been made greater than the remaining diameter of the barrel.The shell is thereby fixed in a specific position inside the barrel. Infiring, the locking element is torn off the shell and remains in thebarrel. Before the mortar can be reloaded the locking element must betaken care of, either manually or with the aid of a special tool.Locking elements therefore entail a further component that has to behandled as part of the weapon logistics system.

The component must be transported, handled by the ammunition handlingsystem, fitted to the shell, removed from the barrel before the nextround can be rammed home, sorted out as scrap and assigned fordestruction or reuse. Due to the high pressure and temperature thatoccur in firing, there is often a risk of the locking element beingburned onto or otherwise adhering to the to the breech opening, which inthe worst case can lead to fracture of the barrel. In order to cope withthe burnt-on component or residues of components, special tools arerequired, which represent extra equipment in the weapons system.Handling the locking element therefore entails a slower and morecomplicated weapons system, in which the risk of barrel fracture isgreat owing to the locking element.

OBJECT AND CHARACTERISTICS OF THE INVENTION

A first object of the present invention is to provide a shell, which isintended for locking in a mortar to prevent movements of the shell whenadjusting the angle of elevation of the barrel prior to firing, withoutthe need to arrange any additional locking components on the shell.

A second object of the invention is to provide a mortar which isdesigned for securing said shell without the need to arrange anyadditional securing components in the mortar.

A third object of the invention is to provide a shell which is designedfor locking in a mortar, which shell will not give rise to any looseparts in the mortar when firing

A fourth object of the invention is to provide a shell for locking,which is simple and inexpensive, and which does not adversely affect theperformance of the shell.

A fifth object of the invention is to provide a system for firing ashell, the system comprising said shell and mortar.

Said objects and other objects not enumerated here are satisfactorilyachieved within the scope of the present independent patent claims.Embodiments of the invention are specified in the dependent patentclaims.

The invention has therefore provided a shell designed for locking in amortar in order to prevent movements of the shell prior to firing,without the need to arrange any additional components on the shell.

According to the invention a mortar has also been provided, which isdesigned for securing said shell without the need to arrange anyadditional components in the mortar.

According to the invention a shell has furthermore been provided forlocking in the mortar, the shell preventing loose parts remaining in thebarrel after firing and the shell being simple and inexpensive, and notadversely affecting the performance of the shell.

Finally, according to the invention a system for firing a shell has beenprovided, the system comprising said shell and mortar.

The essential characteristic of the shell according to the invention isthat the shell comprises a locking part, the locking part forming anintegral part of the shell and the locking part being designed so thatthe shell, after ramming home in the mortar, is locked to acorresponding securing device arranged in the mortar.

According to further aspects of the shell according to the invention:

-   -   the locking part is entirely or partially deformable and the        locking part is releasable in response to a force acting on the        shell in the firing direction A of the shell    -   the locking part is composed of a metal material    -   the locking part is composed of a plastic    -   the shell comprises a rear end and the locking part is an        integral part of the rear end and formed as an end flange    -   the end flange comprises a mechanically weakened section    -   the shell comprises fixed stabilizer fins and the locking part        is an integral of the fixed stabilizer fins and takes the form        of locking heels    -   the locking heels comprise a mechanically weakened section    -   the shell comprises fixed stabilizer fins, the fixed stabilizer        fins being enclosed by a tubular section and the locking part        being an integral part of the tubular section and taking the        form of    -   a tubular flange with a radially projecting part the tubular        flange comprises a mechanically weakened section.

The essential characteristic of the mortar according to the invention isthat the mortar comprises a securing device for securing the shell and abreech closure comprising a contact base, and that the contact basecomprises a securing part comprising at least two securing heels forsecuring the shell.

According to further aspects of the mortar according to the invention:

-   -   the mortar comprises a breech closure, the breech closure        comprising a contact base and the contact base comprising a        securing part    -   the securing part comprises securing heels arranged on the        securing part of the contact rod    -   the securing device comprises a shoulder in the breech opening        of the barrel, the shoulder having been formed in that the        breech opening diameter of    -   the barrel has been made larger than the remaining inside        diameter of the barrel.

The essential characteristic of the system according to the inventionfor firing a shell according to the invention is that the systemcomprises said shell and said mortar.

ADVANTAGES AND EFFECTS OF THE INVENTION

The invention proposed above affords several advantages. No additionalcomponents are needed for locking a shell in a specific position in amortar. The locking part constitutes an integral part of the shell. Thelogistics system of the weapon is simplified, fewer components need tobe handled and transported. The ammunition handling system becomessimpler, faster and less expensive. The shell handling when ramming homeis simplified, no additional components need to be fitted to the shellor disposed of after firing. The risk of barrel fracture due to looseparts being burnt on inside the barrel is eliminated.

According to the invention the locking part may also afford advantageswith regard to the performance of the shell, in that the deformable partof the locking part, the tubular flange, the end flange or the lockingheels are deformed and straightened out directly rearwards.Straightening out directly rearwards is reckoned to have a beneficialeffect on the stabilization characteristics of the shell, since the partdirected rearwards functions as an additional fin.

Further advantages and effects will emerge from a study andconsideration of the following detailed description of the invention,including a number of advantageous embodiments thereof, and the figuresof the drawings attached. The method and the device according to theinvention have been defined in the following patent claims.

DESCRIPTION OF THE DRAWINGS

The invention will be described in more detail below with reference tothe drawings attached, in which:

FIG. 1 schematically shows a shell according to the invention, in whichthe locking part of the shell is arranged in the rear part of the shell

FIG. 2 schematically shows a mortar according to the invention in whichthe shell in FIG. 1 has been prepared for ramming home in the mortar

FIG. 3 a shows a partial enlargement of the securing part of the mortarin FIG. 2

FIG. 3 b shows the shell in FIG. 1 locked to the securing part of themortar after ramming home in the mortar

FIG. 4 a shows the rear part of the shell in FIG. 1 after firing, whenthe stabilizer fins of the shell are deployed and a part of the tubularflange has been deformed and has straightened out rearwards

FIG. 4 b shows the same as in FIG. 4 a from another perspective

FIG. 5 a schematically shows a second embodiment of the shell accordingto the invention in which the locking part of the shell is designed as atubular flange

FIG. 5 b shows a partial enlargement of the tubular flange of the shellin FIG. 5 a

FIG. 6 shows the shell in FIG. 5 a after ramming home in the mortar

FIG. 7 a schematically shows a third embodiment of the shell accordingto the invention in which the locking part of the shell is arranged onstabilizer fins of the shell and consists of locking heels

FIG. 7 b shows a partial enlargement of the rear part of the shell inFIG. 7 a.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a preferred embodiment of a shell 1 according to theinvention. The shell 1 comprises a locking part 3 arranged at the rearend 2 of the shell 1, the locking part 3 constituting an integral partof the shell 1. The locking part 3 is designed for locking the shell 1to a corresponding locking part 9, referred to as the securing part 9,arranged in a ramming mechanism of a mortar 6, see FIG. 2. In ramminghome the shell 1, the shell 1 is locked in the barrel breech opening ofthe mortar 6, following which the shell 1 on firing is released by apredefined force acting on the rear end 2 of the shell 1.

The mortar 6 in FIG. 2 is a motor-driven, automatic breech closureweapon 6, designed for securing the shell 1 according to the embodimentshown in FIG. 1. The mortar 6 is of recoil type and intended for firingshells 1, which can be handled by a mechanical ammunition handlingsystem. The mortar 6 is intended for vehicle-mounting, for mounting onwheeled weapon carriages or for mounting on vessels. The mortar 6 has abreech closure mechanism 8 with a breech closure 10, the movements ofwhich are controlled by an electric servomotor 13 and a digital controlsystem. The servomotor 13, which is mounted directly on the barrel 7,FIG. 2, turns an operating screw, which via a breech closure holder 16powers the movements of the breech closure 10. The movement of thebreech closure holder 16 is controlled by guides 11 and the operatingscrew of the servomotor 13 and locks the breech closure 10 directly inthe rear part of the barrel 7. The breech closure holder 16 has alocking device for locking the breech closure 10 in the barrel 7, thelocking device comprising multiple locking blocks 14 arranged on thebreech closure 10 and a corresponding number of matching locking groovesin the rear part of the barrel 7. Locking is effected by the servomotor13 and the operating screw turning the breech closure 10, so that thelocking blocks 14 are locked in the locking grooves.

As can be seen from FIGS. 3 a and 3 b, contact base 18 (also referred toas the contact rod 18) is arranged in the breech closure 10, againstwhich contact base 18 the shell 1 is secured by a securing part 19.

Since the shell 1 does not have any charge casing, the contact base 18of the breech closure 10 is provided with a rubber obturator of the sametype as used in screw breech mechanism weapons, not shown. As can beseen from FIG. 2, the recoil mechanism of the mortar 6 comprises tworecoil brakes 12, the recoil brakes 12 acting in that they are under agas pressure. The recoil brakes 12 are arranged in a recoil jacket 15,the recoil jacket 15 being of tubular shape and enclosing the rear partof the barrel. The recoil jacket comprises securing devices for therecoil brakes 12 and for elevation axes of the barrel 7, not shown. Thesecuring devices and controls for the recoil jacket 15 are arrangeddirectly on the barrel 7, not shown. Contact devices for electricalfiring of the shell 1 are arranged in the contact base 18 of the breechclosure 10, not shown. Also arranged in the front part of the contactbase 18 are guide grooves for centering the shell 1.

The shell 1 is rammed into the barrel 7 in that the breech closureholder 16 for the breech closure 10 is advanced by means of theoperating screw to a predefined position in the breech opening of thebarrel 7. Throughout the ramming process until the shell is rammed inthe barrel 7, the shell 1 is secured against the contact base 18 in thebreech closure 10. In as much as the contact base 18 does not move inthe barrel 7 after ramming home of the shell 1, it can be used forsecuring the shell 1. The shell 1 is secured by means of a securing part19, which is arranged on the contact base 18, the securing part 19forming an integral part of the contact base 18.

When ramming home the shell 1, the shell 1 is locked in a specificposition in the barrel 7 in that the periphery of the securing part 19is locked against a shoulder 23 in the breech opening of the barrel, theshoulder 23 having been formed in that the breech opening diameter ofthe barrel 7 has been made larger than the remaining inside diameter ofthe barrel 7.

The securing part 19 in FIGS. 3 a and 3 b comprises at least twosecuring heels 20, the securing heels 20 being designed for locking theshell 1 by way of the locking part 3 of the shell 1, FIGS. 1 and 3 b.The locking part 3 of the shell 1 consists of a deformable flange 4, thedeformable flange 4 having been formed in that a cavity or a groove 21,close to the rear end 2 of the shell 1, has been produced, for exampleby milling out, the groove running at least one turn around the shell 1.The dimension 22 of the groove is such that it corresponds to thedimension of the securing heels 20. The loading process means that theammunition handling system of the mortar 6 introduces a shell 1 from theside, so that the securing heels 20 of the securing part 19 are guidedinto the groove 21 in the shell, thereby locking the shell 6 against thecontact base 18 of the breech closure 10.

The flange 4 in FIG. 1 is of deformable design allowing the flange 4 orpart of the flange 4 to be deformed and to straighten out rearwards onfiring, thereby preventing the flange 4 or parts of the flange 4 beingabraded and ending up in the barrel 7. It is preferably only the part ofthe end 2 comprising the flange 4 that is of deformable design, whilstother parts of the end 2, which are exposed to stresses during firing,are not deformable. The flange 4 can be made more or less deformable inthat it is composed of a more or less deformable material and/or bymaking the flange thicker or thinner. The flange 4 is preferablycomposed of a deformable metal, such as a steel alloy, for example.Alternatively the flange 4 may be composed of other types of deformablematerial, such as copper, brass or aluminium or an alloy containing saidmaterials. Plastics and/or composite materials may also be included. Theflange 4 can also be designed with a mechanically weakened section tofacilitate the deformation.

Because the shell 1 is firmly secured throughout the loading process, itcan be rammed home at high speed without the risk of it continuing intothe barrel 7 and losing contact with the contact rod 18 and the contactdevice for electrical firing. A high ramming speed means time-saving anda high rate of fire. In the event of a possible misfire, the shell 1 caneasily be drawn out of the barrel 7 by means of the breech closure 10.The mortar 6 is cable of firing at all angles of elevation, even tippingangles. There is no need to rely on the force of gravity to hold theshell 1 in the correct position. Low angles of elevation can be usedwhen the mortar 6 is to be used for directed fire. Conventional mortarsare limited to angles of elevation of 45-85 degrees, due to the factthat the shell 1 lies loosely in the barrel.

FIGS. 5 a and 5 b show an alternative embodiment of a shell 26 accordingto the invention. The shell 26 is designed with an annular fin section,the annular fin section comprising fixedly mounted fins 29 enclosed by atubular or cylindrical section 27, the rear part of the tubular orcylindrical section 27 being embodied as a tubular flange 28, alsoreferred to as a tube flange 28, the tube flange 28 comprising a flangepart projecting radially outside the shell 26, see FIG. 6. Also arrangedin front of the fin section is a propellant charge for firing the shellout of the barrel 7. The tube flange 28 has two functions, firstly tolock the position of the shell 26 in the barrel 7 and secondly to guidethe shells in an automatic ammunition handling system in the same way asthe casing flange in a conventional cased round. The tube flange 28 inFIGS. 5 a and 5 b here forms the locking part of the shell 26 and locksthe shell 26 in a specific position in the barrel 7 when the tube flange28 is rammed home against a shoulder 23 in the breech opening of thebarrel 7.

The shell 26 is introduced into the breech opening of the barrel 7 inthe firing direction A of the shell by means of the contact base 18, theradially projecting part of the tube flange 28 being pressed against theshoulder 23. In the same way as the end flange 4 in FIG. 1, the tubeflange 28 in FIGS. 5 a and 5 b is of deformable design, in that it iseither composed of a deformable material and/or in that the tube flange28 has been made thicker or thinner and/or in that it comprises amechanically weakened section to facilitate the deformation.

When the shell 26 is fired, the tube flange 28 is bent backwards andforms a part of the fin assembly, which allows the shell 26 free passagethrough the barrel 7, and since the tube flange 28 straightens out itdoes not present any additional air resistance during the trajectoryphase of the shell 26. It is also possible to design the tube flange 28so that after straightening out the tube flange 28 exerts a stabilizingeffect on the flight characteristics of the shell 26.

FIGS. 7 a and 7 b further show an embodiment of a shell 35 according tothe invention. The shell 35 comprises fixed stabilizer fins 36, thefixed stabilizer fins 36 comprising deformable parts, said locking heels37, the locking heels 37 being arranged on rear vane tips of thestabilizer fins 36. The locking heels 37 are an integral part of thestabilizer fins 36 and comprise a part protruding radially in relationto the longitudinal axis B-B of the shell 35. The locking heels 37constitute locking parts of the shell 35 and lock the shell 35 in thatthe radially protruding part of the locking heels 37 is rammed againstthe shoulder 23 when the contact rod 18 presses the shell 35 into thebreech opening of the barrel 7. In the same way as the end flange 4 andthe tube flange 28, the locking heels 37 are of deformable design,either in that that they are composed of a deformable material and/orthat they have been made thicker or thinner and/or in that they comprisea mechanically weakened section.

The shell is therefore locked in a specific position in the breechopening of the barrel in that a flange or locking heel is pressedagainst a shoulder in the breech of the barrel and in that the shell issecured against the contact base, which introduces the shell into thebarrel. This means that the shell cannot move either forwards orbackwards after ramming home. The mortar can be aimed with any angle ofelevation, even tipping angles, without the shell shifting. Aconventional muzzle-loaded mortar requires angles of elevation of atleast approximately 45 degrees in order that the shell will bear againstthe contact base. The mortar according to the invention affords optimumperformance, that is to say the best possible securing of the shell inthe barrel and scope for automatic ammunition handling if shells withannular fins are used. Conventional mortar ammunition of standard typemay also be used in this type of mortar weapon, however. The sphere ofapplication, however, is limited to high angles of elevation, in whichthe shell rests against the contact base under its own weight.

ALTERNATIVE EMBODIMENTS

The invention is not limited to the examples shown but may be modifiedin various ways without departing from the scope of the patent claims.The embodiment of the locking part of the shell and the securing part ofthe mortar can therefore be modified within the bounds of feasibility,provided that no additional components are added or fitted to the shelland/or in the mortar and that no loose or burnt-on parts remain in thebarrel of the mortar after firing.

The invention claimed is:
 1. Mortar for firing a shell intended forfiring from a weapon, wherein the shell is designed for locking a mortarto prevent movement of the shell when adjusting the angle of elevationof the mortar prior to firing, wherein the shell comprises a lockingpart, the locking part forming an integral part of the shell and beingdesigned so that the shell, after ramming home in the mortar, is lockedto a corresponding securing device arranged in the mortar and whereinthe locking part comprises a deformable mechanically weakened section tofacilitate deformation of the weakened section, and wherein the mortarcomprises a securing device operable to secure the shell and a breechclosure comprising a contact base, and the contact base comprises thesecuring part comprising at least two securing heels operable to securethe shell.
 2. Mortar for firing a shell according to claim 1, whereinthe securing device comprises a shoulder arranged in the breech openingof the barrel the shoulder having been formed in that the breech openingdiameter of the barrel has been made larger than the remaining insidediameter of the barrel.
 3. System for firing a shell, wherein the systemcomprises a shell intended for firing from a weapon, the shell beingdesigned for locking a mortar to prevent movement of the shell whenadjusting the angle of elevation of the mortar prior to firing, whereinthe shell comprises a locking part, the locking part forming an integralpart of the shell and being designed so that the shell, after ramminghome in the mortar, is locked to a corresponding securing devicearranged in the mortar and wherein the locking part comprises adeformable mechanically weakened section to facilitate deformation ofthe weakened section and a mortar according to claim
 2. 4. System forfiring a shell, wherein the system comprises a shell intended for firingfrom a weapon, the shell being designed for locking a mortar to preventmovement of the shell when adjusting the angle of elevation of themortar prior to firing, wherein the shell comprises a locking part, thelocking part forming an integral part of the shell and being designed sothat the shell, after ramming home in the mortar, is locked to acorresponding securing device arranged in the mortar and wherein thelocking part comprises a deformable mechanically weakened section tofacilitate deformation of the weakened section and a mortar according toclaim
 1. 5. System for firing a shell according to claim 4, wherein theshell comprises a rear end and the locking part comprises an end flange,the end flange being an integral part of the rear end.
 6. System forfiring a shell according to claim 4, wherein the shell comprises fixedstabilizer fins and the locking part comprises locking heels, thelocking heels being integrally formed with the fixed stabilizer fins. 7.System for firing a shell according to claim 4, wherein the shellcomprises fixed stabilizer fins, the fixed stabilizer fins beingenclosed by a tubular part, the rear end of the tubular part beingformed as a tubular flange.
 8. Mortar for firing a shell according toclaim 1, wherein the shell comprises a rear end and that the lockingpart comprises an end flange, the end flange being an integral part ofthe rear end.
 9. Mortar for firing a shell, according to claim 1 whereinthe shell comprises fixed stabilizer fins and that the locking partcomprises locking heels, the locking heels being integrally formed withthe fixed stabilizer fins.
 10. Mortar for firing a shell, according toclaim 1 wherein the shell comprises fixed stabilizer fins, the fixedstabilizer fins being enclosed by a tubular part, the rear end of thetubular part being formed as a tubular flange.